Garmin NUVI A-GPS?

[Fee]

Hi all. I was just wondering, does the Garmin NUVI series systems have A-GPS? Or does it all take forever to get a signal when switched on unlike mobile phones?

 

[jdjoubert]

What is "A-GPS"?

......... Sometimes, if you switch the GPS off. Then moved your location with a couple of km. Then turn the unit on again............ it needs to cold start. As it kept the previous location in its memory.

It can take up to 5min to do a cold start.

But it should only take 20 to 40 sec under normal conditions.

 

[Dolby]

A-GPS is assisted GPS. I know nothing about it though, other than the fact it uses cellphone towers to pick up your location initially - which means loooong start ups

 

[Fee]

What is "A-GPS"?

......... Sometimes, if you switch the GPS off. Then moved your location with a couple of km. Then turn the unit on again............ it needs to cold start. As it kept the previous location in its memory.

It can take up to 5min to do a cold start.

But it should only take 20 to 40 sec under normal conditions.

now that 5min cold start im talking about. Dolby you are wrong, with A-GPS it takes like literally 5seconds to start up and get a valid gps fix no matter where you are. Now i wanted to know if any of the Garmin systems have the A-GPS built in.

 

[Sackboy]

now that 5min cold start im talking about. Dolby you are wrong, with A-GPS it takes like literally 5seconds to start up and get a valid gps fix no matter where you are. Now i wanted to know if any of the Garmin systems have the A-GPS built in.

They would need a phone built-in. I think only the Tom-Tom has a sim card slot now. Whether it uses A-GPS, I'm not so sure. Most GPS receivers will take a while to get a fix if you haven't used them for a while or moved far from your previous position. From then onwards it's quicker. Also, newer chips help (SIRFSTARIII)

 

[Dolby]

I meant to say 'no looooonger start ups' - sorry

 

[Fee]

Oh i didnt know it was the cellphone networks that have A-GPS, i thought it would be in the GPS Unit itself, the chipset or something.

 

[Aqox]

A-GPS is Assisted GPS, meaning that it uses other means to triangulate your position on earth's surface. A-GPS does NOT use satalites. A-GPS uses cellphone towers, which has a midpoint/centre point in the middle of the station, and which is a known point on the earth's surface. It uses a backend computer to send/receive packets to your phone, and with sending, it gets a speed and distance it takes for the packets to get to your phone, and then with all that data, it gives you your new location. Wikipedia will give you more detail...

Garmin Nuvi does NOT use A-GPS, it uses Satalites, which is GPS tech.

If you're indoors, the GPS will take much longer to start-up.

Thats why most people mount the GPS against their windscreens to get the satalites quicker. If you mount it on the floor where your pedals are, you're unlikely to get any satelites (no line of sight to satelites - same as indoor)

A-GPS is not that slow I must say, i'm using an iPhone, and with Google Earth, i get instant response on where I am. Estimate 3-5sec

Regards,